This invention relates to electroless plating of metals on nonconductor substrates, and in particular to the stability of plating baths and the rate at which they cause plating to occur.
The plating of dielectric substrates by nonelectrical means has a wide range of application, including both decorative and utilitarian purposes. It is of particular utility in the printed circuit board industry, where it is one of the most important steps in the multistep process of the formation of signal trace patterns.
Two of the problems often encountered in electroless metal deposition processes are the dropping out of metal from the plating solution during storage (i.e., spontaneous reduction to the metallic form) and slow deposition rates when in contact with the substrate to be plated. Considering the high cost of the electroless plating baths, it is clear that these problems are detrimental to the industry in the economic sense.